Neuroinflammatory responses of microglia in central nervous system trauma

Abstract

Although relatively few in number compared to astrocytes and neurons, microglia demonstrate multiple, varied neuroimmunological functions in the central nervous system during normal and pathological states. After injury to the brain or spinal cord, microglia express beneficial pro- and anti-inflammatory phenotypes at various stages of recovery. However, prolonged microglial activation following injury has been linked to impaired parenchymal healing and functional restoration. The nature and magnitude of microglial response to injury relates in part to peripheral immune cell invasion, extent of tissue damage, and the local microenvironment.

Keywords: Central nervous system; inflammation; microglia; spinal cord injury; traumatic brain injury.

Figure 1.

Immunofluorescent staining from 5 µm frozen sections (OX-42 primary antibody) demonstrating microglia in uninjured rodent spinal cord (a) in comparison with activated microglia (b) in the ventral horn just caudal to the site of SCI (200×). (Modified from Samantaray et al., Neurochem Res 2011; 36:1809–1816).

Figure 2.

Depiction of divergent microglial inflammatory phenotypes following CNS injury.